Structural Studies Of The Fusion Protein From HearNPV

Enveloped virus infects cells by a series of structural changes of viral envelope fusion glycoprotein.There are two types of membrane fusion proteins on the budded virus of baculoviruses——GP64 and F.The crystal structure of GP64 has been solved,but the F protein has not been.GP64 is the fusion protein for group I NPV,belonging to Class III viral membrane fusion protein.F protein is the membrane fusion protein of group II NPV and GV,and F protein is considered to be a class I fusion protein.The protein is initially synthesized as a precursor(F0),which is cleaved by furin into two polypeptide chains,F1 and F2.These two protein were linked by disulfide bonds.In this thesis,the extracellular domain HaFect(31-611aa)of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus(HearNPV)was stably expressed in DES S2 cells.High purity target proteins were obtained by Ni-NTA affinity chromatography and MonoQ ion exchange chromatography.We use a variety of methods to optimize crystals and obtain diffraction data with anomalous scattering of heavy atoms.The crystal structure of F protein was determined by SAD and other methods.It provides a structural basis for the study on the mechanism of baculovirus infecting target cells and inducing membrane fusion.